Distal radius fractures are among the most common type of bone fracture of the upper extremities. The distal radius fracture is often called a “Colles” fracture (named after a 19th Century British surgeon who described the fracture). The Colles fracture is associated with a fracture of a distal tip or distal end portion of the radius.
Distal radius fractures are, unfortunately, most common in the elderly segment of the population. This is because the elderly tend to exhibit some degree of bone density loss or osteoporotic condition making their bones more susceptible to injury. Indeed, just as osteoporosis is known to affect women more often and more severely than men, distal radius fractures are much more common in females than males, typically on the order of about 20:1. Distal radius fractures generally occur as a result of a fall, because the patient tends to brace for the fall by outstretching the hand which then fractures upon impact, at the distal radius at or adjacent the wrist.
As shown in FIGS. 1 and 2, the distal radius fracture is such that the major fracture line 15 associated with this type of injury generally occurs just above or proximal to the articular joint surface 11 of the distal radius at the wrist about the metaphysis 12. As shown in FIGS. 1 and 2, one common distal radius fracture type separates the shaft 13 of the radius 10 from the distal end portion of the bone. That is, the fracture line 15 defines a first major bone fragment 18 which is located above the fracture line 15 (the distal side) proximate the articular joint surface 11 and extends substantially medially (laterally) across the radius 10 in the metaphysis region. Although not shown, the fracture may also produce smaller bone fragments or splinters along the fracture line. Further, the distal end portion of the radius may be present as multiple (vertically and/or horizontally oriented) fragments disrupting the articular joint surface itself. This latter type of Colles fracture is known as a comminuted intraarticular fracture (not shown).
FIG. 1 illustrates the fracture line 15 in the radius 10 as a substantially horizontal line which produces an upper or distal fracture fragment 18 as a substantially unitary fragment. Similarly, FIG. 2 illustrates a fracture line 15 in the radius 10 which is offset from a horizontal axis.
Distal radius fractures can be difficult to treat, particularly in the older osteoporotic patient. Conventionally, this type of fracture has been treated by a closed (non-surgical) reduction and application of a splint (such as a plaster compression dressing) or a cast (typically circular plaster or fiberglass). Unfortunately, primarily because of the patient's osteoporosis, during the healing process, and despite the splint/cast immobilization, the fracture fragments can settle, potentially causing a collapse at the fracture line in the distal radius. FIG. 2 illustrates a loss of radial inclination (in degrees) and a shortened length in the skeletal length line (shown with respect to a neutral length line “L”) which can occur after a fracture in the distal radius. That is, even healed, these types of fractures may cause shortening or collapse of the bone structure relative to the original skeletal length line. This, in turn, can result in deformity and pain.
Treatment options for a collapsed distal radius fracture are relatively limited. The primary conventional treatments include the use of devices which can be characterized as either external fixation devices or internal fixation devices. External fixation devices are those that stabilize a fracture through the use of percutaneous pins which typically affix one or more bone portions to an external (anchoring or stabilizing) device. Internal fixation devices are those devices which are configured to reside entirely within the subject (internal to the body). Percutaneous pins can be used alone, without anchoring devices, for fixation of Colles type fractures. The use of external devices has conventionally been thought to be particularly indicated in cases of bone loss to preserve skeletal length as noted, for example, in U.S. Pat. No. 5,571,103 to Bailey at col. 1, lines 35–43. However, such devices can be bulky, cumbersome, and or invasive to the user or patient. Further, the external fixation devices may not be suitable for use in soft osteoporotic bone.
In view of the foregoing, there remains a need for improved distal radius fracture treatment devices and techniques.